Stiffener for boots and shoes and process of manufacture thereof



July 20, 1926. 1,593,184

E. LIONNE STIFFENER FOR BOOTS AND SHOES AND PROCESS OF MANUFACTURE THEREOF Filed Sept. 15, 1924 Patented July 20, 1926.

UNITED" STATES PATENT OFFICE.

ERNEST LIONNE, OF SWAMPSCOTT, MASSACHUSETTS.

STIEFENER FOR BOOTS AND SHOES AND PROCESS OF MANUFACTURE THEREOF.

Application filed September 15, 1924. Serial No. 737,719.

This invention relates to stiffeners for boots and shoes, as stiffeners for the box toes, stiffeners for the counters, and the like, of boots and shoes.

Leather is usually preferred,'above other materials, in the manufacture of boots and shoes, by reason of its strength and ability to resist flexing without rupture to a greater degree than its substitutes but it has detrimental characteristics which ordinarily preclude its use as a stiffener. Leather has been used as a stiffener and especially as a box toe stiffener but is relatively expensive and consequently can be used only in the more expensive shoes. Furthermore, leather is not particularly stiff and, consequently, must be relatively thick to provide adequate stiffness. Leather, also, is softened by moisture and consequently may lose its shape.

An object of this invention is the provision of a leather stiffener, especially for box toes, composed of leather impregnated with a stiffening agent which is adapted to be softened by immersion of the stiffener for a short time in a suitable softening agent for the stiffening agent, so that the stiffener becomes pliable and may be lasted, and subsequently becomes dry and hardens in lasted form and regains its initial stiflness, or even increased stiffness, whereby to provide adequate and permanent support for the adjacent part of the boot or shoe.

A further object is to provide an impregnated leather stiffener which is not affected by moisture.

A yet further object is to provide a stiffener which is composed of a porous leather, the fibres of which are coated with a solvent-soluble but water-insoluble stiffening agent, as a nitro-cellulose, while maintaining substantially the porosity of the leather.

A further object is to provide a stiffener composed of chrome tanned leather im. pregnated with a stiffening agent.

A yet further object is generally to improve the construction of stiffeners for boots and shoes.

Fig. 1 is a plan view of a box toe stiffener constructed in accordance with this invention.

Fig. 2 is a. section along line 2-2'of Fig.

Fig. 3 is a more or less diagrammatic representation of the cross-sectional appearance of the impregnated leather stiffener and indicating the coated fibres and the open pores between them.

Fig. 4 is a sectional detail of oneof the fibres of Fig. 3 and showing the stiffening coating on the surface thereof.

While I have herein illustrated a box toe stiffener embodying the invention, the invention may be incorporated in stiffener-s adapted to support other parts of a shoe.

The stiffener embodying the invention comprises a body 10 of suitable shape and composed of chrome-tanned leather. Chrome tanned leather is strong and, while initially water-permeable, is not affected by water or moisture. It can resist flexing without cracking which is not the case with bark tanned leather. Chrome tanned leather is also relatively porous and thus adapts itself especially to my purpose. Chrome tanned leather is used, at present, for parts of shoes other than the stiffeners more extensively than any other kind of leather and consequently there is available a large quantity' of waste chrome leather, at a relatively low cost as compared with the cost of the full hides from which to make my stiffener. While all grades of chrome leather are suitable for my purpose, a chrome leather split is especially suitable for my purpose, as it is especially porous.

As an initial step in the process of manufacture, the stiffener is cut in the desired shape, out of a large piece of leather. The leather sometimes has present in it local hard spots, or localities having decreased porosity and increased stiffness. My process includes treating the leather, and particularly the stiffener blanks, to render them substantially uniformly porous and flexible throughout and the treatment consists in flexing the blanks repeatedly, and particularly at the hardened portions thereof, to loosen the fibres and thereby soften the leather and increase the porosity thereof at such portions. The flexing of the leather blanks may be effected by machine or by hand, and in any suitable manner, as may be desired.

The chrome leather stiffener is then impregnated, in any suitable manner, with a solution containing a stiffening agent, so that the solution penetrates substantially uniformly all parts of the blank. In accordance with this invention the stiffening agent is characterized by being water-insoluble but soluble in a suitable softening agent. I find that a nitro-cellulose is very satisfactory as the stiffening agent. The wet impregnated leather blank is then dried rapidly to evaporate, or practically boil, the solvent out of the stiffener and leave the dry stiffening agent as'a hard film on and in the leather and on and adherently united with the fibres thereof while preserving substantially the porosity of the leather.

If the stiffener is used to support the box toes of shoes, the edge of the dried impregnated stiffener may be skived as as 11" in the ordinary manner.

In the process ofdrying the impregnated leather stiffener, it sometimes happens that a surface film of the stiffening agent more or less covers or seals the surface pores of the leather and thereby retards the penetra-,

move thesuperficial coating and the dried stiffening agent from at least one surface of the impregnated leather stiffener, by buffing. or otherwise, and thereby open or expose the pores of the stiffener to ready penetration by the softening agent. I find that, or-

dinarily, it is sufficient merely to remove the surface film on one face'of the stiffener as the softening agent rapidly penetrates the stiffener by reason of the porosity thereof.

While buffing a surface of the stiffener acts to open the surface pores of the impregnated stiffener, it also .acts to increase appreciably the surface areaof the stiffener, by reason of the irregular surface produced by the buffing operation, and consequently increases the ability of the impregnated stiffener to take up the softening agent, and thereby re-. duces the time required to soften the stiffener and, furthermore, permits the stiffener to become more thoroughly softened.

The stiffener thus constructed may readily be softened by immersion in a suitable softening agent, which with a nitro-cellulose as a stiffening agent, may comprisea mixture of ether and alcohol. The softened stiffener may be lasted into shape and when dry will regain its initial stiffness oreven increased stiffness Figs. 3 and 4 may serve to illustrate more or less diagrammatically the cross-section of the impregnated leather stiffener and also a section of one of the fibres thereof. The fibres 15 of the impregnated stiffener have a coating 16 of the stiffening agent, while the pores 17 of the stiffener are substantially empty or, at least, are not completely filled with the hard stiffening agent.

The treatment set forth above retains the initial resiliency of the leather; and the chrome leather stiffeners, thus prepared, and in contradistinction to a bark-tanned leather stiffener, or to leather substitute stiffeners, is elastic and yet practically unbreakable.

I claim:

1. A new article of manufacture comprising a stiffener for boots and shoes composed of a leather blank which is impregnated with a soluble stiffening a ent, said impregnated stiffener characterize by being porous and readily penetrated by a softening agent for the soluble stiffening agent.

2. A new article of manufacture comprising a stiffener for boots and shoes composed of a chrome leather blank which is impregnated with a soluble stiffening agent, said impregnated stiffener characterized by being porous and readily penetrated by'a softening agent for 'the soluble stiffening agent.

3. A new article of manufacture comprising a stiffener for boots and shoes composed of a leather split blank which is impregnated with a soluble stiffening agent,said

impregnated stiffener characterized by being porous and readily penetrated by a softening agent for the soluble stiffening agent.

4. Anew article of manufacture comprising a stiffener for boots and shoes composed porous and readily penetrated by a solvent for the nitro-cellulose.

6. A new article of manufacture comprising a stiffener for boots and shoes composed of a chrome leather blank which is impregnated with a nitro-cellulosic stiffening agent,

said; impregnated stiffener characterized by being porous and readily penetrated by a solvent for the nit-ro-cellulose.

In testimony whereof, I have signed my name to this specification.

ERNESTI LIONNE. 

